Tuyển tập các báo cáo nghiên cứu về lâm nghiệp được đăng trên tạp chí lâm nghiệp quốc tế đề tài: The effect of elevated atmospheric CO concentration 2 and nutrient supply on gas exchange, carbohydrates and foliar phenolic concentration in live oak. | 379 Ann. For. Sci. 56 1999 379-389 Inra Elsevier Paris Original article The effect of elevated atmospheric CO2 concentration and nutrient supply on gas exchange carbohydrates and foliar phenolic concentration in live oak Quercus virginiana Mill. seedlings Roberto Tognettia b c Jon D. Johnson3 a School of Forest Resources and Conservation University of Florida 326 Newins-Ziegler Hall Gainesville FL 32611 USA b Istituto per 1 Agrometeorologia e 1 Analisi Ambientale applicata all Agricoltura Consiglio Nazionale delle Ricerche via Caproni 8 Florence 50145 Italy Department of Botany Trinity College University of Dublin Dublin 2 Ireland Received 15 July 1998 accepted 4 November 1998 Abstract - We determined the direct effects of atmospheric co concentration CO on leaf gas exchange phenolic and carbohydrate allocation in live oak seedlings Quercus virginiana grown at present 370 pmolmol or elevated 520 pmol-moF1 CO for 6 months in open-top chambers. Two soil nitrogen N treatments 20 and 90 pmol-moF1 total N low N and high N treatments respectively were imposed by watering the plants every 5 d with modified water soluble fertilizer. Enhanced rates of leaflevel photosynthesis were maintained in plants subjected to elevated CO over the 6-month treatment period in both N treatments. A combination of increased rates of photosynthesis and decreased stomatai conductance was responsible for nearly doubling water use efficiency under elevated CO . The sustained increase in photosynthetic rate was accompanied by decreased dark respiration in elevated CO2 . Elevated CO led to increased growth rates while total non-structural carbohydrate sugars and starch concentrations were not significantly affected by elevated CO treatment. The concentration of phenolic compounds increased significantly under elevated CO . Inra Elsevier Paris. elevated COJ gas exchange nitrogen phenolics Quercus virginiana I total non-structural carbohydrates Resume - Effet d une concentration .
